bluebird boxes: be a good landlord

THE NEIGHBOR WHO HANGS BAGS of giant homegrown shallots on my gate also has rules and regulations. “Bluebird Rules and Regulations,” to be specific, as in: How to be a good bluebird landlord, minimizing hazards for the beloved birds with specific nestbox tips and tricks.

Deb's bluebird houses in fieldDeb, my “next-door” neighbor despite the uphill mile of dirt road between us, installed her first nestbox more than 20 years ago. Today, she has a trail of 24 boxes on her farm in Columbia County, New York, where she spends much of bluebird season (here, that’s March through August) “worrying over my little charges,” she says.

guard for bluebird boxq&a: deb’s bluebird rules and regulations

Q. Where did you learn to be a good bluebird landlord?

A. I rely heavily on Bet Zimmerman’s website Sialis.org and a wonderful little pamphlet called “Enjoying Bluebirds More” by Julie Zickefoose, and I always urge (implore, really) people interested in putting up nestboxes to read Bet’s page of bottom-line advice for new bluebirders. [Note: Sialia sialis is Latin name for the bluebird’s genus and species. Also: Zickefoose wrote a whole book on the subject called “The Bluebird Effect” in 2012.]

Q. So what’s the basic thrust of your Bluebird Rules and Regulations? 

A. My boxes are installed to encourage successful nesting by the bluebirds by minimizing the many threats they face throughout their season. Before nesting season even begins, I make sure my boxes are cleaned from the previous season.

I also apply a coat of Ivory soap to the ceiling to prevent wasps’ nests, and I attach a bit of plastic netting to the inside of the box opening to serve as a “kerf” (a little ladder that fledging bluebirds can climb to reach the exit hole, photo below).

kerf for bluebirdsThen I do a little dance to bring good luck because, well, you never know.  Last week, as I was rubbing Ivory soap on the ceilings of my 24 boxes, I was thinking how amazing it is that these beautiful creatures survive at all considering the many threats they face while nesting.  Here are a few:

  • Aforementioned wasps’ nests;
  • Blowfly larvae who feed on nestlings during prolonged rains or drought;
  • Raccoons, snakes and rats who steal eggs and kill nestlings;
  • Cats who stalk;
  • Competition from tree swallows and wrens;
  • Nestlings that are unable to climb out of the box at fledging time (necessitating those “kerfs” I mentioned earlier);
  • And most dire of all, the dastardly house sparrow.

Q. What’s the key to success, if there is one? Sounds like a lot of possible trouble can occur. 

A. The most important advice I can offer is to use a nestbox specifically designed for bluebirds, locate it properly and monitor it throughout the nesting season. [Get Cornell NestWatch’s plans for bluebird and other species-specific bird boxes.]

Spring comes, we hear that cheerful throaty song and we are moved to put up a home for the bluebird.  We rush to buy a birdhouse, nail it to a fence post and think we have done a good deed for the bluebirds. If your readers take away only one idea it is this: An improperly located and unmonitored nestbox will quickly become a bluebird death trap.

Q. How do we avoid that?  

A. Bluebird Rule #1:  Resist all temptation to hammer a box onto the nearest tree, the side of a building or fence post. Doing so will almost certainly bring disaster to the bluebirds and heartache to you.

A raccoon, rat or snake can easily climb that wooden post to steal eggs and kill nestlings. Instead, your nestbox should ideally be mounted on conduit pipe that a raccoon can’t easily climb, fitted below with a baffle or predator guard (photo below; predator guards can be made from stove pipe) and located in an open, grassy area at least 100 feet away from shrubs or other natural “cover.”  Nestboxes should face away from prevailing winds, which generally means facing south. If you are lucky enough to have tree swallows, you will want to have a pair of nestboxes, back to back, about 15 to 25 feet apart (like in the top photo).

guard 2 for bluebird houseThen, follow Bluebird Rule #2: Do everything possible to prevent house sparrows from invading. Bet Zimmerman says on her website, “Successful bluebird landlords do not tolerate house sparrows…which are non-native nest site competitors. In my opinion, it is better to have no nestbox at all than to allow house sparrows to breed in one.”

I agree and I think it bears repeating: It is better to have no nestbox at all than to put one up where there are house sparrows, which are invasive alien predators and one of only a few bird species that are not protected by the Migratory Bird Act of 1918. (The European starling is another species not protected by this Federal law, but it is too big to fit into the entry hole of a properly sized bluebird nestbox. The house sparrow, on the other hand, is smaller than a bluebird and can easily fly into the box.)

Q. What are signs of house sparrow invasion?  

A. The first is a trashy-looking nest that includes weeds, straw, and garbage in a big arc curving up the back of the box. The second–and most disturbing–sign is a dead bluebird inside the box. If you find a dead bird inside the box, chances are very, very high that it was trapped and killed by a marauding house sparrow. Bet recommends a number of ways to manage house sparrows.

Q. So besides proper siting, the right box, and reckoning with house sparrows, what other care is essential to being a good landlord?

A. Bluebird Rule #3: Once erected, monitor your nestbox. To quote from “Enjoying Bluebirds More:”

“A bluebird box put up and never monitored is like a letter never sent.”

In addition to monitoring for house sparrows, I also watch for blowfly larvae, which suck on nestlings during prolonged periods of stressful weather conditions like drought or rain. I even keep a spare dry nest on hand to swap out if a nest gets wet or infested (but I admit I do not recommend this for the inexperienced bluebirder).

sparrow spooker 2I also watch very carefully for the first bluebird egg. Once that first egg has been laid, nothing will keep the female out of the nestbox, so that is when I put up a sparrow spooker (above and below)–basically a stick with lots of reflective streamers hanging off it. The flapping, blowing streamers scare the house sparrows and deters them from entering. (If I were to put up the sparrow spooker before the bluebird lays her first egg, she too would be deterred from using the box, so I only put it up after that first egg is laid.) Really good instructions for making a sparrow spooker are here.

sparrow spookerQ. Beyond the box regimen, are there other rules we need to follow?

A. The last (but not least) important advice I have is really up your alley, Margaret, and that is to create a backyard paradise by planning and planting for bluebirds.

To quote again from “Enjoying Bluebirds More:”  “What use is a bedroom if there is no kitchen?”

Bluebirds, like all other wild species, are under increasing pressure from habitat loss. Planting fruiting trees and shrubs helps the bluebirds thrive year-round. Because bluebirds have a fondness for ground-hugging prey, every time we mow our lawn, we create ideal foraging conditions for bluebirds. Water is also a great lure for bluebirds who love to bathe, even daily.

Q. Any last words?

A. Nothing makes me happier than seeing fledglings leave the box for the first time. I wish all of your readers great success in their careers as bluebird landlords. And, may all your blues be birds!

extra: why are bluebirds blue?

WHY ARE bluebirds blue? The obvious answer seems to be, “Because they have blue feathers,” but that’s not it, says a segment on the public-radio show BirdNote. It’s all about the feathers’ structure—and the light trick they create right before our eyes. Listen in to learn what’s going on. (Photo by Joanne Kamo courtesy of BirdNote.)

(All other photos except bluebird, above, and top photo of dirty box by my neighbor Deb, used with permission.)

  1. Cami McSween says:

    Thank you for your great article. We have our first Bluebird nest going. Wish I knew ahead about fledgling ladder.

  2. Patti Day says:

    I’ve had four bluebird nests for twelve years. Bluebirds frequently nest twice a year, once in early spring and again a couple weeks after raising their first brood, so there have been many blue bird offspring from those four boxes. One important thing I learned early. Don’t paint your boxes. I once painted a box to match my house. Poor mother bluebird. She was so hot, she was actually sweating and panting because the house couldn’t breathe. The bluebird pair successfully raised their nestlings in spite of my dumb mistake. Those boxes are left natural for a reason.

  3. Jody says:

    We have a bluebird house that has been used by bluebirds for several years, but we want to replace it. Our bluebirds are scouting early and we’re still waiting for the house to be delivered. They’ve been around a lot, but haven’t started building a nest. Is it too late to replace it?

    1. margaret says:

      I don’t know where you live, Jody, but in the Northeast where I am there is probably still a little time for a swap. They are scouting here late February onward but usually don’t settle on a spot right away, and in fact often get nudged aside by later-arriving tree swallows and go find alternate spots!

  4. Ody says:

    I’m from NW Indiana. We have 2 bluebird houses. One is to the back of our yard-where we can still see it from our kitchen window. We have heard that the 2nd needs to be 100 ft from first…..we are TRYING to keep the sparrows out by cleaning it daily-sometimes a couple times a day. We can’t seem to get bluebirds in that one-even though they are a good 50 ft apart. Any suggestions??

  5. Lia says:

    I have an urgent question. I have a bluebird box on the side of my property facing an empty lot. There is no fence between my property and this empty lot. The bluebirds will be hatching sometime this week. Well, I just found out that they are going to start building a house on the empty lot! I don’t know what to do. If a put a privacy fence up it may be hard for the bluebirds to land and take off and I don’t want them to abandon the box if they get bothered by the construction workers and all the commotion. Should I move the box a few feet away? Will they leave the baby birds? Also, would it be bad of me to take away the box after this brood is gone? I would feel bad for the parents but it will get more hectic with construction going on. Please help.

    1. margaret says:

      Hi, Lia. I think bluebirds take 2 to 3 weeks from hatching to fledging. I would hesitate to do anything to a nest with eggs in it. And I suspect that your putting up a piece of fence would be a disturbance, too, no? Maybe the construction won’t get too far in the next couple of weeks? I would move the nest box after this brood fledges; sounds like no pair will want to use it anyhow with the commotion. This is a dramatic example of why so many birds never make it to adulthood.

  6. Patty says:

    Just put up my first house and bluebirds came immediately! Several couples have been checking it out for weeks every morning before 8am and then we don’t see them again the rest of the day. No activity inside the box… Is this all normal? It’s mid-April in Ohio – did we miss the window? When do they start building a nest?

  7. Debbi Jawad says:

    I enjoyed your article on blue birds. I have had blue birds and boxes for many years. I usually have blue birds in them but not this year. ?? No birds are using any of the 5 boxes I have up this Spring. ?? I cleaned them out in the fall. i do have all sorts of birds at the bird feeders , plenty of blue birds. I have had tree swallows in one box before. But I took that box in for repair and neglected to put it out yet. Any ideas of why none of the boxes are being used this spring?

  8. Rebecca Robinson says:

    I appreciated your article about how to for bluebird nests. So far we have not done anything right. It seems I bought a pretty birdhouse this year and I put it where we can see it from the back deck and we noticed a pair of bluebirds in our backyard that moved in. There are multiple eggs in the nest and the parents are being attentive. We are crossing our fingers that we will get to see a new family that thrives. It has been thrilling for all of us.

  9. Benny Mays says:

    Do you clean out box after the birds leave the nest in Arkansas I have had birds that raise another family, another thing people may not know is that blue birds use to nest in the top of wooden fence post until metal replaced them, there was a wildlife officer in Michigan (I Think) that made houses with mesh wire covering a hole in the top and had great success with them this was 5-6 years ago, I had chickadees to nest in one of my houses and have left it and a male bluebird is checking it out, would you clean the nest out, Thanks

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